We sought to assess whether ADSCs isolated from diabetic rats could be considered a reliable candidate for autologous stem cell therapy in diabetes by investigating the impaired signalling pathways involved in regulating oxidative stress and apoptosis.
Diabetes was induced in rats with a single intra-peritoneal injection of streptozotocin (STZ). The ADSCs were isolated from rats with diabetes (dADSCs) and rats without diabetes (nADSCs). Colony-forming unit (CFU) assay was used to compare colonies derived from dADSCs and nADSCs. Reactive oxygen species (ROS) formation and total antioxidant power (TAP) were also measured. In addition the expression of antioxidant enzymes including CAT, SOD1, SOD3, GPx1, GPx3 and GPx4 were measured at mRNA level by RT-PCR. The protein expression of Bax, Bcl2, Caspase-3, total and phosphorylated JNK and P38 MAPK were analyzed by western blotting.
The present results indicated that the cell viability and plating efficiency of dADSCs was significantly decreased compared to those of nADSCs. ROS generation was enhanced in dADSCs. The gene expression of antioxidant enzymes of CAT, SOD1, GPx3 and GPx4 significantly enhanced in dADSCs compared to nADSCs, but SOD3 and GPx1 showed opposite reaction. It has also shown that Bax/Bcl-2 ratio, caspase-3 expression and JNK and P38 MAPK phosphorylation were increased in dADSCs compared to nADSCs.
It could be concluded that in diabetes status, hyperglycemia induced-ROS may impair the cellular functions of dADSCs. This impairment seems to be mediated by JNK, P38 MAPKs, and mitochondria pathway in companion with reduction in total antioxidant capacity.